ch 9 notes II - Ch. 9, part 2: Intelligence Genetic and...

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Unformatted text preview: Ch. 9, part 2: Intelligence Genetic and Environmental Influences continued
There is a stronger correlation for identical (monozygotic) than fraternal (dizygotic) twins between: IQ Scores Amount of gray matter in frontal lobes, Wernicke's area Does this mean genes--> more gray matter-->higher IQ? (lower IQ is associated with gray matter reduction/abnormality) Possible third variable: Temperament-related activity level/stimulation Types of Environmental Influences Shared Environment Prenatal
C DZ twins more similar than other 50%-shared DNA pairs C Moreso than MZ twins--resource competition The disappearing twin Familial
C Adoption studies Greater similarity for those reared together Microenvironments Factors in one's surroundings elicited by one's interests and disposition
C Activity level C Types of hobbies Genetic influence on these may operate in separate households
C Accounting for part of variance in MZ twins reared apart 140 130 120 IQ 110 100 90 80 Reaction Range
Impact of Environment Genetically-driven abilities Actual abilities Over the course of development... Group Differences in Intelligence
Group 1 Scores 1 SD (15 points) higher Given... 50% of IQ is genetic 50% of IQ is environment Group 2 Scores 1 SD (15 points) lower Does it follow that... 7.5 IQ points due to genes? 7.5 IQ points due to environment? Consistent and sizeable differences in IQ across racial groups:
Asian Americans Similar pattern for GRE testing: Higher scores White Americans Hispanic Americans Black Americans
QuickTimeJand a TIFF (Uncompressed) decompressor are needed to see this picture. Within-Group versus BetweenGroup Differences
See figure 9.7 The central issue is why do some racial groups perform more poorly on intelligence tests than others? An error has been made historically: Genetics must account for at least half the difference; This is both logically and empirically flawed. The orchard analogy: It is true that individual differences in a crop of trees in the same orchard MUST be due to genetics. BUT, racial groups do not tend to have the same environmental conditions. The genetically-disadvantaged tend to flourish in enriched environments:
e For IQ: Good schools, nutrition, low stress home environment, high parental involvement, etc. The reaction range is greatly limited for everyone in impoverished environments The factors accounting for variations within-groups do not apply to variations between-groups. Impoverished environments affect IQ more than enriched environments b/c genes aren't able to "express" themselves properly-e reduced microenvironmental effect. Current perspectives: IQ tests and many standardized tests are less familiar tasks
C C Practice can improve performance on any task. Racial groups differ in exposure to verbal, quantitative and spatial skills that match the test demands: Books, videogames, board games, etc. Compared to more "practical" measures such as using objects creatively C African children excel at these tasks. The gap seems to be shrinking overall. Keep in mind that the group means may differ, but there is much overlap in distributions of scores across races. Broad shifts in intelligence The Flynn Effect
C IQ increase of ~3 points every 10 years in Western society C Suggested reasons: Kids function more independently in a more complex world Nutrition Speed of processing (interactive games and short-attentionspan culture) The Pygmalion Effect Self-fulfilling prophecy creates "bloomers" Preparing for Exam 2 Be familiar with the end of ch. 9 as well: Esp. the mental retardation - giftedness spectrum Review of Key Concepts Identify the type of Learning in 7 vignette's: Identify the following from Ch. 7 (Memory): Two characterics of memory stores: Sensory, STM, LTM Primacy Effect and Recency Effect What factors increase likelihood of retention? Types of LTM How would you respond to someone claiming that we have a "memory bank" that we can access as long as we are given enough guidance to find the right memory? Ch 8 (Language) Stop on page 346 (before Words,Images, Concepts) Ch. 8 and 12: Discuss critical and sensitive periods as they apply to: Recognition of phonemes Learning vocabulary or sign language Learning a first language (syntax) Prenatal development and teratogens ...
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